# Adherence to Recommended Immunisation Schedules for Patients With Inflammatory Bowel Disease (IBD) on Biologics: A Retrospective Study at Our Lady's Hospital, Navan, Ireland

## TL;DR

This study found that IBD patients on biologics at a hospital in Ireland have low vaccination rates, highlighting the need for better adherence to immunization schedules to reduce infection risks.

## Contribution

The study provides a retrospective analysis of vaccination adherence in IBD patients on biologics in a specific hospital setting, identifying critical gaps and proposing targeted interventions.

## Key findings

- Vaccination coverage was generally low, with influenza and SARS-CoV-2 vaccines having zero uptake among eligible patients.
- Only 45.5% of patients received Tdap, and 25% received meningococcal vaccines, indicating significant adherence gaps.
- All patients with VZV data showed immunity, but no herpes zoster vaccination documentation was found.

## Abstract

Introduction

Patients with inflammatory bowel disease (IBD), particularly those receiving biologic therapies, are at increased risk of infections due to immunosuppression. Vaccinations play a vital role in reducing this risk, yet adherence to immunisation schedules remains suboptimal. This audit aimed to assess vaccination coverage among IBD patients on biologic therapies at Our Lady's Hospital, Navan, Ireland, and to identify areas for improvement.

Aim and objectives

The primary aim was to evaluate adherence to recommended immunisation schedules for IBD patients on biologics. Specific objectives were to assess uptake of vaccines including tetanus, diphtheria, and pertussis (Tdap), meningococcal, measles, mumps, and rubella (MMR), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza, herpes zoster, human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis A virus (HAV), and varicella-zoster virus (VZV), to identify gaps in coverage, and to propose interventions to improve adherence.

Methods

A retrospective review of 24 patients with IBD receiving regular biologic infusions at the hospital's day ward was conducted. Data collected included demographics, type of IBD, biologic therapy details, and vaccination status. The assessment was based on the European Crohn's and Colitis Organisation (ECCO)-aligned immunisation recommendations. Immunity to VZV was accepted based on documented infection history or serological confirmation.

Results

Among the 24 patients reviewed, 14 had ulcerative colitis and 10 had Crohn's disease. Sixteen were male and eight female. Twenty patients were on infliximab and four on vedolizumab. Vaccination coverage was generally low: Tdap (5/11, 45.5%), meningococcal (1/4, 25%), MMR (1/2, 50%), SARS-CoV-2 (0/4, 0%), influenza (1/10, 10%), HPV (1/3 eligible females, 33.3%), HBV (2/15, 13.3%), and HAV (0/4, 0%). All six patients with VZV data showed immunity. No documentation was available for herpes zoster vaccination.

Conclusion

The audit revealed significant gaps in adherence to vaccination guidelines among IBD patients receiving biologics. These findings highlight the need for systematic interventions to improve vaccine uptake, such as routine immunisation status reviews during clinic visits, improved documentation practices, patient education on vaccine safety and necessity, and stronger collaboration between gastroenterologists and primary care providers. Educational materials should be provided during clinic or infusion appointments to address vaccine hesitancy and misinformation. Implementing these changes could reduce the burden of vaccine-preventable diseases in this vulnerable population.